Late Infantile Epileptic Encephalopathy: A Distinct Developmental and Epileptic Encephalopathy Syndrome
Abstract number :
1.189
Submission category :
4. Clinical Epilepsy / 4A. Classification and Syndromes
Year :
2023
Submission ID :
175
Source :
www.aesnet.org
Presentation date :
12/2/2023 12:00:00 AM
Published date :
Authors :
Presenting Author: Shawn Kacker, D.O. – CCHA
Douglas Nordli, M.D. – University of Chicago; Audrey Oetomo, APN – University of Chicago; Chalongchai Phitsanuwong, M.D. – University of Chicago
Rationale:
Within the spectrum of developmental and epileptic encephalopathy (DEE), late infantile epileptic encephalopathy (LIEE) is the least recognized. However, LIEE has distinct clinical and electrographic features that set it apart from the neighboring DEE syndromes of early-infantile developmental and epileptic encephalopathy (EIDEE), infantile epileptic spasm syndrome (IESS), and Lennox-Gastaut syndrome (LGS). Our objective is to shed light on the unique characteristics of LIEE by analyzing patients who exhibit prototypical features. Within the spectrum of developmental and epileptic encephalopathy (DEE), late infantile epileptic encephalopathy (LIEE) is the least recognized. However, LIEE has distinct clinical and electrographic features that set it apart from the neighboring DEE syndromes of early-infantile developmental and epileptic encephalopathy (EIDEE), infantile epileptic spasm syndrome (IESS), and Lennox-Gastaut syndrome (LGS). Our objective is to shed light on the unique characteristics of LIEE by analyzing patients who exhibit prototypical features.
Methods:
From July 2022 to May 2023, we searched for LIEE features in pediatric patients who underwent EEG studies or epilepsy follow-up at the University of Chicago Comer Children's Hospital using congruent clinical history as a guide.
Results:
Out of 850 patients evaluated, thirty patients (3.5%) were identified with LIEE based on electroclinical characteristics. These patients had an average onset of epilepsy at 6.8 months and an average onset of LIEE features at 18.1 months. The epilepsy etiology was most commonly genetic and metabolic (50%), followed by congenital malformations (23%), acquired structural abnormalities (20%), and unknown (7%). The predominant seizure types were myoclonic-tonic (70%), spasm-tonic (50%), epileptic spasms (47%), tonic (43%), and myoclonic (43%) seizures, with all patients experiencing spasm-tonic and/or myoclonic-tonic seizures in addition to other types. All patients had an EEG characterized by periods of discontinuity, electrodecrement, or both with diffuse slowing, a background voltage between 100-300 mV, and superimposed multifocal and/or diffuse epileptiform discharges. Every patient, except one, also fulfilled the definition of drug-resistant epilepsy and all reported either moderate to severe or severe developmental delay.
Conclusions:
Late infantile epileptic encephalopathy (LIEE) is characterized by several unique clinical and electrographic features. Typically, LIEE manifests in patients during the second year of life and occur before two years of age, hence late-infantile onset. The condition is commonly observed in individuals with a propensity for epilepsy. Myoclonic-tonic and spasm-tonic seizures are the quintessential seizure types associated with LIEE. The inter-ictal EEG exhibits more organization and lower voltage than seen with hypsarhythmia and lacks the defining EEG characteristics of EIDEE, IESS, or LGS. Given these distinguishing features, LIEE should be recognized as a distinct syndrome within the spectrum of developmental and epileptic encephalopathies.
Funding: N/A
Clinical Epilepsy